Joiner’s Preparation of a Surface of Wood Under Transparent Processing
Clear processing with alcohol, shellac and nitrocellulose varnishes is the main type of furniture processing. It does not cover the colors and drawings of wood, but, on the contrary, its structure and texture. The transparent finishing layer must have a certain hardness, elasticity, water resistance, etc.
Transparent treatment of furniture and joinery is: that it does not change the visible texture of the wood, coloring the wood, and imitating the texture of a more expensive breed. In practice, the following types of transparent furnish for furniture are provided: polishing, polishing, covering with colorless or colored transparent varnishes, waxing.
GOST 7016 – 54 characterizes the cleanliness of the wood surface depending on the presence of pile and mossiness ( irrespective of the method of processing ) by numerical indicators of inequalities ( roughness and mossiness ).
This GOST provides for ten classes of surface cleanliness. Higher is 10th grade. Under the polishing treatment requirements to the surface are made on the 10th, under varnishing – on the 9th class. Cleaning of the surface to be treated in production conditions is carried out on standards or with the help of special instruments. Joiner’s surface preparation for transparent processing is done especially carefully.
Cleansing. The stripper to be cleaned should have a sharp and straight blade of the gland with a slight rounding at the ends. The humpback neck should be tightly adjusted to the gland and not more than 0. 5 mm from it . The span should be very short . After cleaning , the surface should be smooth and smooth . There should be no teasing in areas of swirling or curl . The hardwood wood is cycled after stripping
Grinding . Surface grinding is recommended by sanding along the layer . In cases where the wood is glued with layers in different directions ( in mosaic ) and the hardness of the individual parts of the set is approximately the same, it is necessary to grind in the direction of the layers of the largest part of the elements. If on the surface there is hard and softwood, then grind in the direction of the layers of softwood.
Grinding starts with a new sanding cloth, and then only the grinders work. During operation, the skin should be cleaned of chips ( dust ); for this purpose, it is often knocked out or cleaned with a solid bristle brush
For grinding of the firm and dense wood which gives a fine pile during processing, small sand is used; for grinding loose and soft rocks – great. Shimmer, slate, crocus and grated brick powder are used for fine grinding of wood, preferably solid and dense rocks of dark color. As a grinding material also used marsh tail, the leaves of which contain small particles of silica ( sand ).
The polished surface should be perfectly smooth, clean in light and silky to the touch. In the mass production of high – quality furniture, panel surfaces intended for lacquering or polishing are sanded on sanding belt machines with a rolling table.